The invention relates to a process for a system employing worms to process an asbestos containing material (ACM). The vermiprosessing system of the present invention includes a vermicomposting technique for reducing the asbestos fiber content of the ACM, with the ability to convert the material into a non-regulated ACM, or further process the ACM into an asbestos free material.
xe2x80x9cAsbestosxe2x80x9d is a generic term, commonly employed in a broad reference to the fibrous or xe2x80x9casbestiformxe2x80x9d varieties of naturally occurring minerals, which fall into two groups: Serpentinite, commonly referred to as xe2x80x9cchrysotile,xe2x80x9d and amphibloe, which includes rebecktite, also referred to as xe2x80x9ccrocidolite,xe2x80x9d cummongtonite-grunerite, also referred to as xe2x80x9camosite,xe2x80x9d and anthophyllite, actinolite and tremolite asbestos. Typically, asbestos materials possess the desirable qualities of high tensile strength, flexibility, and resistance to chemical and thermal degradation. Asbestos is also a superior insulator, due to its high electrical resistance and low heat transfer. These properties have made asbestos a popular component for a variety of commercial and industrial products, from automotive brake pads and protective suits for firefighters, to home siding and boiler insulation.
On a microscopic level, the asbestos mineral is fibrous in structure. Asbestos fibers naturally form bundles or xe2x80x9cfibrils,xe2x80x9d which are long and thin, and separate easily. Because of their fibrous structure, asbestos fibers are relatively easy to observe and count. Employing xe2x80x9cpolarized light microscopy,xe2x80x9d or PLM techniques, asbestos fibers are accurately identified. Asbestos fibers exhibit a dramatic response to polarized light, especially when enhanced with specific, high refractive index oils. Standards for the identification and quantitative analysis of asbestos in materials are well documented in applicable government regulations and microscopy texts. Specifically, methods EPA/600/R-93/116 and EPA/600/M8-82-020, are current standards for the determination of asbestos in bulk insulation materials.
This high level of scrutiny ofxe2x80x9casbestos containing materialxe2x80x9d (ACM), stems from the fact that most health and public safety agencies deem airborne asbestos fibers a substantial health risk and hazard. According to the United States Environmental Protection Agency (EPA), asbestos is a toxic substance and a known carcinogen. Although it is commonly accepted that most people do not become ill from normal, background levels of asbestos, asbestos exposure is considered a health concern when high concentrations of asbestos fibers are inhaled over a long period of time. The EPA has established a series of stringent regulations, as mandated by the Clean Air Act of 1984, which strictly require a proper handling of ACM. The primary regulation in this regard is found in 40 CFR, Chapter I of the xe2x80x9cNational Emission Standards for Hazardous Air Pollutantsxe2x80x9d (NESHAP), specifically the part beginning at xc2xa761.140, titled xe2x80x9cSubpart Mxe2x80x94National Emission Standards for Asbestos,xe2x80x9d and collectively referred to herein as xe2x80x9cAsbestos NESHAP.xe2x80x9d
To minimize the potential for public exposure to elevated levels of asbestos fibers, when asbestos materials are encountered in demolition or construction, the current regulations, which include the Asbestos NESHAP, require extensive safeguards in the removal and handling of asbestos and materials that contain asbestos. ACM is typically present in some component of any modem building or ship, manufactured prior to the public scrutiny of asbestos as a health risk. These suspect components typically include the wrapping of any vessel, tank, boiler, heat pipe or duct. The regulations focus care and concern on the ACM that most likely presents a public health threat. Specifically, when ACM is encountered in demolition, renovation or construction activities, the EPA first requires identification of asbestos containing materials, all of which must be handled in accordance to the Asbestos NESHAP as a xe2x80x9cregulated asbestos containing materialxe2x80x9d (RACM). This material is often removed, rather than xe2x80x9cencapsulatedxe2x80x9d and maintained in place, as a preventative measure to minimize the potential for public exposure to elevated levels of asbestos fibers.
Presently, most asbestos removal is performed by certified workers employing manual methods and procedures, as required under the Asbestos NESHAP. Such manual methods include gloves and simple hand tools. Prohibited, mechanical removal methods tend to abrade, grind or in some way pulverize the ACM. Typically, the ACM is carefully moistened, manually removed, and placed into bags. The bags are then transported to a landfill certified for the receipt of such materials. However, this disposal process is time consuming and expensive. The bags must be handled several times on the way to a safe disposal. The risk of breakage or loss in transport is significant Additionally, a land fill""s RACM disposal fees are prohibitively expensive. This high expense arises in part from the liability and safety issues associated with such disposal, and the strict regulatory oversight for RACM disposal. Because of the expense of proper RACM disposal, the unscrupulous may be tempted to circumvent the rules and improperly remove and illegally dispose of RACM, generating much more of an environmental problem than if the asbestos was left in place and undisturbed.
Besides landfills, other method for the disposal of asbestos have been proposed and implemented with varied success. An example is U.S. Pat. No. 4,678,493 to Roberts et al., which discloses an asbestos waste vitrification process. High temperature vitrification or xe2x80x9cglasifying,xe2x80x9d at temperatures above 1000xc2x0 C., is employed to literally melt asbestos into a glass at high temperatures, rendering it safe for conventional disposal in a landfill. This process apparently works very well on pure asbestos and mineral asbestos mixtures. However, only a small percentage of a typical ACM is asbestos. Most of the ACM is non-mineral, non-asbestos material. Hazardous combustion products from plastics, cellulose materials and organic toxics represent a threat to public health and so are a great concern to regulators. The efficient and effective removal of airborne, unprocessed asbestos from the fly ash, are all significant issues that prevent the widespread use of this process.
Chemical treatment processes that degrade asbestos have also been developed to remediate ACM. U.S. Pat. Nos. 6,005,158 and 6,160,195 to Sugama et al., disclose the use the use of a xe2x80x9csuper acidxe2x80x9d mixture, including concentrated fluoric and phosphoric acids. The super acid is apparently able to digest asbestos containing materials, converting them into environmentaily benign components, predominantly comprising quartz.
In any event and regardless of the conventional or unconventional method employed, the safe and effective removal and disposal of RACM is time consuming and expensive. The safety and expense of the incineration and acid digestion are apparent, as discussed above. These unconventional processes, as well as the conventional removal and landfill disposal methods are fraught with procedural difficulties. Complexity and expense opens many opportunities for mismanagement, with a high likely-hood of failures in oversight and error, resulting in accidental release of asbestos fibers to the air. The fact of the matter is that the landfilling of asbestos may only be a short term solution with a chain of liability traceable to every handler and owner of the ACM. A safer, permanent, more effective and more economical process for the remediation and disposal of ACM is needed.
Recently, the common earthworm has become increasingly popular for use as a composting agent in the processing of organic waste materials. Earthworms readily digest food waste or similar debris, often mixed with paper and other organic materials to form an xe2x80x9corganic feed stock.xe2x80x9d The organic feed stock is ingested by the worms over time to produce a compost product that is especially suitable for garden soil or farm tillage. A conventional worm composting, or xe2x80x9cvermicompostingxe2x80x9d operation centers around a xe2x80x9cworm bin,xe2x80x9d which is a container for housing the combined worms and organic feed stock.
U.S. Pat. No. 4,108,625, to Okada discloses a worm bin apparatus that efficiently composts vegetable matter with the worms to produce a natural, organic fertilizer. U.S. Pat. No. 4,285,719 to Criss also discloses an organic material recycling device that employs a worm organism, specifically xe2x80x9cEsenia fetida,xe2x80x9d to compost human solid waste.
The use of earthworms for composting on a large scale has also been considered. U.S. Pat. Nos. 4,971,6161 and 5,082,486 to Glowgowski describes the processing of municipal garbage with a regenerating earthworm bed.
However, the actual use of earth worms for processing feedstocks other than the organic materials conventionally utilized in vermicomposting, has met considerable difficultly. This is especially true in any attempts to introduce toxic substances to the worms, in hopes that the worms could somehow ingest these toxic materials and render them safe, or environmentally benign. However, the worms, being living organisms, are sensitive to toxins. The processing of toxic materials by vermicomposting has universally resulted in severe impacts upon the health of the worms, and more typically to the death of the worms so employed.
Asbestos, as discussed above, is a toxic material. Not only is asbestos apparently toxic to humans, but it has been asserted as being fatal to the common earthworm varieties employed in conventional vermicomposting. A study titled xe2x80x9cEarthworm Response to Asbestos-Rich Serpentinitic Sediments,xe2x80x9d performed at the University of British Columbia, in Vancouver B.C., Canada, by the Department of Soil Sciences, as published in the Journal of Soil Biology and Biochemistry, Vol. 18, No. 1, pp 85-90 (1986), attempted to process asbestos containing soils with common earthworms of the variety Lumbricus ruhellus. The mortality rates of the worms were dramatic, and analysis of the short survived worms showed high levels of asbestos within. Just as a person skilled in the art of vermicomposting would likely expect, based upon the well established toxic nature of asbestos fibers, the worms were unable to effectively ingest and process asbestos.
Therefore, with the failings of these above experimenters and the apparent need for a truly safe and efficient method for the remediation of ACM, an apparatus or technique is still needed that provides an environmentally safe and efficient process of the remediation of ACM. The inventors of the present invention have addressed many of the issues as presented above in the development of a new method for asbestos remediation. The present invention will be better understood by reference to the following detailed description taken in conjunction with the accompanying drawings.